# Columnstore index functionality
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This topic provides reference information about the compatibility of columnstore indexes when migrating from Microsoft SQL Server 2019 to Amazon Aurora PostgreSQL. Aurora PostgreSQL does not offer a directly comparable feature to SQL Server’s columnstore indexes, which are used for data compression and query performance improvement in data warehousing scenarios.


| Feature compatibility |  AWS SCT / AWS DMS automation level |  AWS SCT action code index | Key differences | 
| --- | --- | --- | --- | 
|   ![\[No feature compatibility\]](http://docs.aws.amazon.com/dms/latest/sql-server-to-aurora-postgresql-migration-playbook/images/pb-compatibility-0.png)   |   ![\[No automation\]](http://docs.aws.amazon.com/dms/latest/sql-server-to-aurora-postgresql-migration-playbook/images/pb-automation-0.png)   |  N/A  |   Aurora PostgreSQL offers no comparable feature.  | 

## SQL Server Usage
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SQL Server provides columnstore indexes that use column-based data storage to compress data and improve query performance in data warehouses. Columnstore indexes are the preferred data storage format for data warehousing and analytic workloads. As a best practice, use Columnstore indexes with fact tables and large dimension workloads.

### Examples
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The following example creates

```
CREATE TABLE products(ID [int] NOT NULL, OrderDate [int] NOT NULL, ShipDate [int] NOT NULL);
GO

CREATE CLUSTERED COLUMNSTORE INDEX cci_T1 ON products;
GO
```

For more information, see [Columnstore indexes: Overview](https://docs.microsoft.com/en-us/sql/relational-databases/indexes/columnstore-indexes-overview?view=sql-server-2017) in the *SQL Server documentation*.

## PostgreSQL Usage
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 Amazon Aurora PostgreSQL-Compatible Edition (Aurora PostgreSQL) doesn’t currently provide a directly comparable alternative for SQL Server columnstore index.